I'm going to try to find a meter that I can hook-up at the battery to show how much current is being drawn from the battery at any given time when the engine is turned off.

Unfortunately, this is not an easy task. Ammeters need to be in SERIES with the circuit in order to read current draw. If you simply put this at the battery terminal, you will subject the meter to the full several hundred amp draw of the starter. Tough finding a meter that can handle that, yet still read fine scale milliamps for an overnight test. Same with a shunt type arrangement that's typically used for starter motor testing.

The better way is to not include the heavy wire that goes to the starter motor, and only tap into the wiring that goes to the underhood junction box and beyond. Now at least you keep the peak current down below 100 amps (below 50 if you are careful what you turn on in your testing).

What you want to avoid is any meter arrangement where you have to break the circuit in order to insert the meter, as this interruption will no doubt change the very nature of what you are trying to test. For instance, if it's a subsystem on-board computer issue and you turn it off and back on, it might not now respond as it might have thru the course of a normal engine shutdown.

As you are probably aware, there are certain systems that act in a 'stepdown' mode after shutdown. Some things don't go to sleep for 20 minutes or so. Other things, like the Evap Monitor (an OBD-II test), don't come alive until approximately 5 hours after shutdown. Unless you put a chart recorder on the ammeter, it's unlikely you will see all that is going on.

Hey fibber2, thank you very much for the head-up's.Here's my plan for the ammeter...all testing to be done with the engine off, disconnect the negative battery terminal, apply the contact probes of the ammeter to get a baseline amps reading. If things are working correctly, there should be a minimum specified/acceptable range of draw for the computer(s) as long as nothing unexpected is pulling current. I'll get a idea of that baseline from the Toyota techs.If the draw is greater than it should be, we start individually pulling fuses and cateloging the readings for each one, hopefully narrowing down the circuit that's affected.And yes, I'm aware of the evap monitor and the "step-down" modes (i.e. some Ford trucks have 30 minute step-downs), and planned on having the van shut-off and untouched for an hour before we start.Again, thanks so much, and any other thoughts and advice are appreciated. Regards, honyoker

Update: After getting the all clear (Battery, Alternator & slow drag) from the Dealer last weekend I was especially cognizant to make sure all lights were off this week and that the fans and stereo were turned off before I turned off the engine. Van started struggling to start by thursday and by the time we tried to start the van up on Saturday morning it was dead yet again. I only drive about 3.5 miles one way to drop off kids and head to work so I don't know if I'm just not giving the alternator enough time to re-charge the battery?....Still Frustrated and starting to wish I had bought the Honda.

P.S. My dealer did test to see if there was any battery draw after it was shutdown and mentioned that a certain draw was normal and that my van was in the normal range.

Depending on the exact conditions of those cold starts and that short 3.5 mile drive, you may indeed be guilty of taking out more than you are putting in.

A cold start load could pull up to 400 amps. Accepted, it's a brief duration at that draw rate, but it's from a chemical conversion and not an unlimited current source.

While your alternator may be rated at a lofty 130-150 amps, that assumes the engine is spinning at 2k RPM or so. If it is a low speed drive with some stop & go, and you have lights and fans running, you might not be putting much back into the battery at all. Plus, given that you have to put back something like 2-3X or more to equal what you took out (energy conversion efficiency), you might be running in depletion mode all the time.

Experiment. Drive a few extra miles each night before coming home. Some high speed driving would be a plus. Do this for a week and see if things are any better.

I came across this forum when I was doing a search on issues that I am having with my vehicle. I have a 2006 Sienna with automatic sliding doors. I have been having battery draining issues and dome lights that are on even when the switch at the front is set to OFF. I actually leave that switch to off permanently because I've been through 2 batteries in 2 years due to the battery draining when I didn't realize the dome lights and the running lights were staying on. I pulled the lightbulb out of the running lights so it wouldn't be on all the time.

In November of last year, the sliding doors malfunctioned and injured by 8 year old. The retraction system was not working and it hit her waist/hip, her shoulder, and then hit her face, ending up with a gash above her eye, needing stitches. (I created a blog about it here: http://toyotamalfunction.blogspot.com)

I didn't think that the electrical issues could have been related to the malfunction on the retraction system. Something to consider.

northbrook4 you still here?My son's van, like your, checked-out "OK" with the dealer AGAIN, but we didn't get any specifics as usual. He's asked for a "file" to be opened with Toyota (a specific process for unresolvable complaints/problems) wherein eventually Toyota will assign some sort of "master mechanic" who will come in, examine every test the dealer's done and dig further into the matter to get it corrected. In the meantime, son and I will be doing our own disagnostics with my new multimeter. We'll keep you posted.

Had a hole in signal lens on right signal light burned out socket for bulb ...replaced socket still no signal lights checked fuses. Signal lights do not come on flashers do not work. Indicator lights in dash do not work. Cannot even hear clicking noise.

I even put the car in the driveway, started the engine with the door OPEN (and my finger on the door switch), and fiddled with the switch until I replicated both the "unlock" and interior lights problem.

Solution: I added a ~1/8" thick x 1" x 3" piece of adhesive-backed rubber over the part of the door that triggers the switch. No. More. Problem. Our problem was with RIGHT hand turns, so I found some VERY aggressive right hand turns to test it out...all is good!

Thanks for the post, this really helped me focus in and solve the problem!!

@martin152 said:
I solved my electrical mystery, perhaps this will help someone else.
I have a 2000 Sienna XLE. Whenever I turned left my dome lights/map lights would turn on and the door ajar light would come on. After I completed the turn, all would go back to normal.
The solution was really too simple. On the inside of the passenger door there is "bump" or protrusion that makes contact with the rubber covered switch that turns the map lights on. At some point in time, someone must have slammed the door on the metal seat belt latch and dented the protrusion. When the door closes it still makes contact with the switch to turn of the lights and the "open door" warning, but when turning left the centripetal force of gravity allows just enough pressure to be removed from the contact of the switch to turn the lights on.
I fixed it by taking a small piece of cardboard and folding it over a couple of times to thicken it up, then I took a piece of "Gorrilla Tape" and taped the piece of cardboard on top of the "protrusion" on the door.
It sounds silly, I know, but I've never had the problem since.
At some point in time I might screw a thick washer onto the "Bump", but for now cardboard and gorilla tape seems to work just fine.
I hope this helps someone.